Automatic Procedure for Aeromechanic Analysis of Turbomachinery Blade-Rows

The main purpose of the turbomachinery industry is to develop more efficient and environmental friendly engines. The modern design trend is to decrease the number of stages and blade count leading to thinner and lighter profiles. At the same time, this trend entails engines blade-rows more prone to flutter and forced response issues. This paper presents an integrated tool-chain to investigate aeroelastic phenomena automatizing the overall procedure. The method is based on the open-source FEM solver (CalculiX) and on the in-house CFD code (TRAF). The combined use of these solvers requires BCs exchanges from solid to fluid domain and vice versa. For this purpose, a dedicated tool-chain was implemented: it allows the automatic transfer of the blade mode shapes, computed by the FEM solver, to the CFD domain for flutter analyses (URANS computations with moving blade). On the other hand, the tool-chain is used to transfer the unsteady pressure field, computed by an unsteady CFD analysis on the blade surface, into the solid model in order to perform a forced response evaluation. Both these BCs exchanges require the overlapping of CFD and FEM meshes on the blade surface. To do so, an automatic method to find out the rotation matrix and translation vector between the two different domains is integrated in the tool-chain. The procedure has been tested on 1 and 1/2 low pressure transonic compressor stage and the numerical results are compared with experimental data acquired in the context of the EU FUTURE project. Such comparisons confirm the applicability of the procedure in the blade-row design loop.